Study Scope

The scope of work of the Matanuska-Susitna Borough Risk MAP Study includes (see also the map below):

Detailed hydrology and hydraulic modeling to include 71.9 miles of riverine study, perform approximate riverine analysis for 316.6 miles, and delineate 15.4 miles of existing areas. Floodplain boundaries will be updated for the 1-percent and 0.2-percent-annual-chance (100- and 500-year) flood events. The rivers to be updated include:

Updated detailed modeling (Zone AE) will be completed for:

Little Susitna River (including Split Flows 1-3) = 39.2 mile

Willow Creek = 13.3 miles

Willow Creek Tributary = 7.1 miles

Limited detail modeling (Zone A with structures) will be completed for:

Wasilla Creek = 10.7 miles

Updated Approximate Studies (Zone A) will be completed for:

Upper Matanuska River = 14 miles

Point MacKenzie = 2 miles – roughly from Walsop Road to 2 miles downstream of Walsop Road

US Army Corps of Engineers (USACE) Studies (Leverage - Zone AE) will also be incorporated to include:

Matanuska River = 3.9 miles

Knik River = 2.7 miles

Bodenburg Creek = 5.7 miles

Preparation of a regulatory Flood Insurance Study (FIS) Report document to the Community. A FIS is a book that contains information regarding flooding in a community and is developed in conjunction with the FIRM. The FIS, also known as a flood elevation study, frequently contains a narrative of the flood history of a community and discusses the engineering methods used to develop the FIRM. The study also contains flood profiles for studied flooding sources and can be used to determine Base Flood Elevations for some areas.

Preparation of a regulatory Flood Insurance Rate Map (FIRM) map for all panels within the Community which identifies the Community's flood zones, base flood elevations, and floodplain boundaries. This map is used to determine where the purchase of flood insurance is required for properties with federally-backed mortgages. The preliminary FIS and DFIRM’s are scheduled to be released in September 2015.

Collect LiDAR in Summer 2015. This data will be delivered to the community by Fall 2015.

All of the above datasets will be in the in the North American Vertical Datum of 1988.

The State and FEMA will provide guidance, feedback, coordination and technical support throughout the Risk MAP Project Life Cycle.

Project Status

The project is currently in the production stage. The following table illustrates project status and includes major milestones with dates: